Repeated immunosensing by a dithiobis(succinimidyl propionate)-modified SAW device

Screen Printing Tissue Models Using Chemically Cross-Linked Hydrogel Systems: A Simple Approach To Efficiently Make Highly Tunable Matrices

In vitro models provide a good starting point for drug screening and understanding various cellular mechanisms corresponding to different conditions. 3D cultures have drawn significant interest to mimic the in vivo microenvironment better and overcome the limitations of the 2D monolayered cultures. We previously reported a technique based on the screen printing process to pattern live mammalian cells using gelatin as the bioink. Even though gelatin is an inexpensive scaffolding material with various tissue engineering applications, it might not be the ideal hydrogel material to provide various mechanical and chemical cues to the cells. In this paper, we discuss the synthesis and characterization of two synthetic chemically cross-linked hydrogel systems based on poly(ethylene glycol) (PEG) and poly-l-lysine (PLL) to be used as the bioink in the screen printing process. These hydrogels are suitable as the bioinks for the screen printing process and serve as the barebone materials that can be tuned mechanically and augmented chemically to create a suitable in vitro microenvironment for the cells. This paper presents the synthesis, mechanical testing, and characterization of the hydrogel systems and their applications in the screen printing process.

A Novel Rapid Test to Detect Anti-SARS-CoV-2 N Protein IgG Based on Shear Horizontal Surface Acoustic Wave (SH-SAW)

Since the Coronavirus disease 2019 (COVID-19) pandemic outbreak, many methods have been used to detect antigens or antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including viral culture, nucleic acid test, and immunoassay. The shear-horizontal surface acoustic wave (SH-SAW) biosensor is a novel pathogen detection platform with the advantages of high sensitivity and short detection time. The objective of this study is to develop a SH-SAW biosensor to detect the anti-SARS-CoV-2 nucleocapsid antibody. The rabbit sera collected from rabbits on different days after SARS-CoV-2 N protein injection were evaluated by SH-SAW biosensor and enzyme-linked immunosorbent assay (ELISA). The results showed that the SH-SAW biosensor achieved a high correlation coefficient (R = 0.9997) with different concentrations (34.375–1100 ng/mL) of the “spike-in” anti-N protein antibodies. Compared to ELISA, the SH-SAW biosensor has better sensitivity and can detect anti-N protein IgG signals earlier than ELISA on day 6 (p < 0.05). Overall, in this study, we demonstrated that the SH-SAW biosensor is a promising platform for rapid in vitro diagnostic (IVD) testing, especially for antigen or antibody testing.

A digital single-molecule nanopillar SERS platform for predicting and monitoring immune toxicities in immunotherapy

The introduction of immune checkpoint inhibitors has demonstrated significant improvements in survival for subsets of cancer patients. However, they carry significant and sometimes life-threatening toxicities. Prompt prediction and monitoring of immune toxicities have the potential to maximise the benefits of immune checkpoint therapy. Herein, we develop a digital nanopillar SERS platform that achieves real-time single cytokine counting and enables dynamic tracking of immune toxicities in cancer patients receiving immune checkpoint inhibitor treatment - broader applications are anticipated in other disease indications. By analysing four prospective cytokine biomarkers that initiate inflammatory responses, the digital nanopillar SERS assay achieves both highly specific and highly sensitive cytokine detection down to attomolar level. Significantly, we report the capability of the assay to longitudinally monitor 10 melanoma patients during immune inhibitor blockade treatment. Here, we show that elevated cytokine concentrations predict for higher risk of developing severe immune toxicities in our pilot cohort of patients.

There is a clinical need to monitor immune-related toxicities of immune checkpoint blockade therapy. Here, the authors develop a digital SERS platform for multiplexed single cytokine counting to track immune-toxicities and demonstrate the ability to use pre-screening to identify patients at higher risk.

Antibody immobilization techniques in mass sensitive immunosensor: enhanced sensitivity through limited mass load

Background:

Biosensors are analytical devices that include a sample-delivery approach between a biological recognition element and a transducer required to convert the physicochemical change produced from the interaction of biological molecules-receptor interaction into signal. The immunosensor is a special type of biosensors that includes an antibody as a biorecognition element to detect analyte as antigens. In mass-sensitive sensors, antigen-antibody interactions can be specified by measuring the frequency change and most commonly knowns are surface acoustic wave, bulk acoustic wave, quartz crystal microbalance and microcantilevers.

Methods:

Different methods for antibody immobilization including functionalization of the transducer surface with specific groups have been reported for antibody immobilization. This stage affects the limit of detection and overall performance. In this review, perspectives on immobilization strategies of mass sensitive immunosensors according to transducer types will be presented. The choice of immobilization methods and their impact on performance in terms of capture molecule loading, orientation and signal improvement is will also be discussed.

Results:

One of the most critical point during configuration of the biorecognition layer is to improve the sensitivity. Therefore, we initially focused on comparisons of the antibody immobilization strategies in the biorecognition layer in terms of mass load level and high sensitivity.

Conclusion:

The lack of significant data on the mass accumulations up to the functionalization and antibody immobilization steps, which are the basis of immusensor production, has been identified. However, mass sensitive immunosensors have the potential to become more common and effective analytical devices for many application areas.

Sensitive and selective colorimetric probe for fluoride detection based on the interaction between 3-aminophenylboronic acid and dithiobis(succinimidylpropionate) modified gold nanoparticles

APBA was conjugated on DSP@AuNP to form stable APBA–DSP@AuNP, exhibiting high selectivity towards fluoride against other anions and glucose.